optimize: traverse children with WINDOW_FIRSTCHILD/WINDOW_NEXT

sw/source/core/view/viewsh.cxx

@@ -370,15 +370,16 @@ void ViewShell::ImplEndAction( const sal_Bool bIdleEnd )
                     if ( GetWin() )
                     {
                         Window& rWindow = *(GetWin());
-                        if(rWindow.IsChildTransparentModeEnabled() && rWindow.GetChildCount())
+                        if (rWindow.IsChildTransparentModeEnabled())
+                        {
+                            Window* pCandidate = rWindow.GetWindow( WINDOW_FIRSTCHILD );
+                            if (pCandidate)
                             {
                                 const Rectangle aRectanglePixel(rWindow.LogicToPixel(aRect.SVRect()));
 
-                            for ( sal_uInt16 a(0); a < rWindow.GetChildCount(); a++ )
+                                while (pCandidate)
                                 {
-                                Window* pCandidate = rWindow.GetChild(a);
-
-                                if ( pCandidate && pCandidate->IsPaintTransparent() )
+                                    if ( pCandidate->IsPaintTransparent() )
                                     {
                                         const Rectangle aCandidatePosSizePixel(
                                                         pCandidate->GetPosPixel(),
@@ -390,6 +391,9 @@ void ViewShell::ImplEndAction( const sal_Bool bIdleEnd )
                                             pCandidate->Update();
                                         }
                                     }
+
+                                    pCandidate = pCandidate->GetWindow( WINDOW_NEXT );
+                                }
                             }
                         }
                     }